Add sun position automatic uniform.
Prototype data source plugins
Start adding sun rendering.
first take on extent rotation
replace quaternion rotate with matrix rotate
Ongoing data source prototyping.
relocated declaration of rotation matrix
sample - adding link
Merge branch 'master' into sun

Conflicts:
	Source/Scene/SceneTransitioner.js
Frustum cull the sun.
Add fragment shader for pretty lame looking sun.
Update sun fragment shader.
Draw sun after the sky atmosphere.
Merge branch 'master' into sun
Merge branch 'master' into dataSources
partial solution for #718
Merge branch 'master' of github.com:AnalyticalGraphicsInc/cesium into jsdoc
fixed sample link
Ongoing data source prototyping.
Merge branch 'master' into dataSources